This weekend, the third installments of the summer’s most anticipated trilogies will go head to head: the guys-gone-wild extravaganza “The Hangover Part III,” the highest grossing R-rated comedy franchise of all time, and the indie romance “Before Midnight,” perhaps the lowest-grossing (but critically beloved) franchise in cinematic history.

The “Before” series, which director Richard Linklater calls his “accidental trilogy,” has become over the past 19 years a longitudinal study of relationships: the films bring together actors Julie Delpy and Ethan Hawke as Jesse and Celine, the young lovers who met on a train in “Before Sunrise,” and rekindled their romance in Paris nine years later in “Before Sunset.” In the latest installment, the couple—married now, and with kids—is on holiday in Greece, struggling to keep their flame alive as once-charming quirks start to grate on each other’s nerves.

At a Greek restaurant in Midtown Manhattan, Linklater talked with Speakeasy about the challenges of long-term relationships, shooting long scenes, and the pressures that come with releasing an indie trilogy:

Speakeasy: When did the discussions start to do a third movie?

Richard Linklater: About three years ago it seemed like Jesse and Celine were asserting themselves. It’s like, we work for them. With the second one, Julie and Ethan came to Austin about five years after the first film—they did a little scene in my [2001] film “Waking Life”—and that’s when we looked at each other, and were like, “That wasn’t just happenstance. We do work well together.” That put us on the path. This time, it was easier to make that leap, but harder to do what we were digging into.

Is that because in the first two films, Celine and Jesse are under these enormous time constraints, and now they’ve got their whole lives together?

Yes, it made it that much more difficult, structurally. It’s a harder story to tell. It’s not as romantic sounding, is it?

How did you figure out what the story would be?

It was a blank canvas – we could’ve done anything, really. We could have had another encounter, if they were married to other people. We started from when “Before Sunset” fades out. We started thinking, what’s different at their age now? You don’t just take two weeks off and go to Europe and ride around on a train. You can’t do that once you have dependents or a certain place in life, most people. It would have been not as believable. So we felt we had to dive into the domestic. We had an early idea of just a typical Wednesday in their life, they’re both working and there are kids to pick up. We were on that for like six months. Then we thought what if they’re on holiday? But all that domestic stuff still works.

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Richard Linklater on May 21, 2013 in Los Angeles, California.

Could you talk about what you were trying to show about relationships?

Inevitably, what attracts you to someone isn’t what makes a great long-term partner. Couples get over each other. There are a lot of relationships where it’s like “We used to camp all the time!” And then, the other person says “I hate camping! I only did that because you did.” You realize you’re bending to what you think they need. We’re all trying to fit, to make it work. That’s the endlessly fascinating subject, how people negotiate their time and space around each other in life.

Did you go back and watch the other two before you started writing the third one?

I do, because I’m analytical that way. It’s harder for Ethan and Julie, because it’s them and they think they know it. But they’ll be talking about the script and suggest something, and I’ll say “That’s in the first movie! We did that already! Watch the movies!” Once we all got to Greece, 10 weeks before shooting, we did sit down and watch both films back to back. It helps you dial in, because they aren’t really those two characters. They have personal relationships with them, but there’s a difference between Julie and Celine, and there’s a difference between Ethan and Jesse.

When you met with them in Greece, was the script finished?

No, we were still writing. We just sat down and did the hard work, in the room all day and night. It’s a very writerly process that segues into workshopping then rehearsing. Then there’s the moment when it’s like, “I’m making a movie and they’re acting in the movie.” We’ll be rewriting on the day [of shooting]. I’ll drop a line in between takes. But they have a lot of dialog to memorize and a lot of rehearsal.

These films aren’t at all improvised, which often surprises people.

It’s a huge compliment to them as actors. I mean, have you ever seen a 10-minute improvised scene that fit into the rest of the movie? No, you haven’t. Because it’s impossible. People who know performing know that’s impossible. With a long single take, people have this belief that the audience will see it as kind of real on some level, but it discounts the enormous effort required, not to mention ability. Not all actors can do that, or would even want to.

It’s almost like a stage production.

The stage lends itself to real-time acting. Film doesn’t really support that in the same way—with where the light falls, all these people walking, the sound boom. Flaws can happen. You have to bend the film apparatus to support it, and it drives everybody crazy, but it’s worth it. I think Ethan and Julie have been under-credited as actors. But “2001: A Space Odyssey” didn’t get nominated for best costume design for the apes at the beginning, because everybody thought they were real apes.

What you’re saying is that Julie and Ethan are so natural, it’s hard to appreciate that they’re acting?

When you play the deformed person, people go “Oh, what great acting!” Any actor will tell you that’s kind of easier because it’s out of the ordinary. To get that familiar is just hard to do. That’s our row to hoe.

How did you decide what city to set this in?

It becomes the third character, the co-lead. It comes late. Paris [the setting of “Before Sunset”] was obvious. [Celine] lived there. It made sense. But the first and third films were harder. This one, it could have been Greece, Italy, Spain, could have been Maine. Greece just worked. It just felt like the right place. That writer’s house [where they stay while on vacation], I visited that place. I was in Greece two days last May and I found that and so many of the other locations—that, the hotel room, the little town. I was like “This is pretty good. Yeah.”

Did any of you ever think in 1994 that this would become a trilogy?

We’re the accidental trilogy. You’d never been that presumptuous to think that way. As we started talking about the second one, I remember Ethan being like “What about this kinda life project?” It was just theoretical. There was never any long-term thinking. Every movie you could theoretically do a sequel to. Like an old friend you haven’t seen in a while, you figure, they’re having their life. But it’s rare that it physically manifests, “Oh here’s Jesse and Celine, nine years older!”

I made that joke at Sundance. I am glad she’s internalized that. I said, “We are going to skip the next three or four, and then do a comedic remake of ‘Amour.’” That would make me really old, because I’m older than them.

Since there’s been such a long gap between these films, there must be lot of pressure to live up to people’s expectations.

There are no victory lap sequels here. You can’t take that much time and not dig in. I think people forgive economic sequels that give people more of what they liked. Most sequels get worse and worse, and they reboot franchises and that’s its own world. This trilogy has so nothing to do with that. There’s no real economics involved. Nobody’s clamoring for us to do this. We’re always at the same barely make-able budget.

What was the budget?

About $3 million, which is just a little more than the other two. It’s funny—from ’94 to ’03 it was the exact same budget.

Both “Before Sunrise” and “Before Sunset” became cult hits long after they made it to theaters. What do you think of day-and-date releases?

I am not against it theoretically, especially if you live in a place where you have to drive three hours to get to an independent type theater. I grew up in that place, where you’d hear about stuff and it never came to town. So you are left with this resentment about elites—these 20 places that have the culture. The day people combine theatrical and VOD [and publicly release the results] you’ll see more of it, but I don’t think anyone wants the stigma of a film that only did well on VOD. You can’t blame Hollywood for making films for 13 year olds, because that’s who goes to the movies. I keep telling people who have kids, “You’re out of the demographic.” They say, “I can’t even go to a movie anymore” and I say “That’s why Hollywood makes films not for you.”

About Speakeasy

Speakeasy is a blog covering media, entertainment, celebrity and the arts. The publication is produced by Barbara Chai and Jonathan Welsh with contributions from the Wall Street Journal staff and others. Write to us at speakeasy@wsj.com or follow us on Twitter at @WSJSpeakeasy or individually @barbarachai.